3D printed airtight insulated objects using fused deposition modeling
We disclose methods for, devices that implement, and structures produced by 3D printing of insulating and airtight walls using fused deposition modeling printers. Several disclosed methods and features contribute to insulating and airtight walls. These can be used individually or in combination. Structures that reduce or eliminate horizontal surfaces through the use of overlying cantilevered contours can be combined with continuous structures that penetrate through multiple layers, selective overfilling, offset joints and additional extrusions to mitigate leakage routes. Self-supporting closed cell structures can be built that form insulating regions by controlling convective losses.
1. A method of creating an airtight cap structure, by additive manufacturing, including:
depositing, by fused-deposition-modeling, a base layer with at least two abutting contours forming a perimeter of a structure and defining a contained gap;
depositing by fused-deposition-modeling an initial cantilevered layer with at least two abutting contours over the base layer, wherein one contour in the initial cantilevered layer
spans the two abutting contours of the base layer,
overlaps each of the two abutting contours of the base layer by at least 40 percent of a width of the one contour, and
is fused in contact with both of the abutting contours of the base layer;
depositing by fused-deposition-modeling additional cantilevered layers with at least two abutting contours over the base layer, wherein the additional cantilevered layers
overlaps each of the two abutting contours of immediately underlying layers by at least 40 percent of a width of the one contour,
are fused to the immediately underlying layers and
decrease the contained gap between the abutting contours in the base layer; and
depositing by fused-deposition-modeling an upper enclosing cantilevered layer over an upper additional cantilevered layer wherein the contained gap is sealed by the enclosing cantilevered layer.
2. The method of claim 1 , wherein the upper enclosing layer includes four abutting contours.
3. The method of claim 2 , further including doubling the upper enclosing cantilevered layer, including:
depositing by fused-deposition-modeling in a step layer a pair of non-abutting step contours that each overlap two abutting contours of the upper enclosing cantilevered layer; and
depositing by fused-deposition-modeling a doubling cantilevered layer of at least two abutting contours over the pair of non-abutting step contours that double seals the contained gap.
4. The method of claim 1 , further including:
in the base layer, depositing multiple pairs of abutting contours, one pair enclosing an other pair, defining at least two contained gaps; and
in the additional cantilevered layers, depositing by fused-deposition-modeling multiple pairs of the abutting contours over and fused to immediately underlying multiple pairs, wherein the multiple pairs in a cantilevered layer decrease the contained gaps.
5. The method of claim 1 , wherein at least one pair of abutting contours includes two concentric contours with non-aligned end butts.
6. The method of claim 5 , further including radially distributing end-butt joints in the concentric contours to avoid alignment between the end-butt joints in both vertically and horizontally adjoining concentric contours.
7. The method of claim 1 , wherein at least one pair of abutting contours is formed by a continuous spiral extrusion.
8. The method of claim 1 , further including defining one or more vents in the airtight cap structure with gaps in the deposited contours.
9. An airtight cap structure, manufactured by additive manufacturing, applying the method of claim 1 .
10. An airtight cap structure, manufactured by additive manufacturing, applying the method of claim 2 .
11. An airtight cap structure, manufactured by additive manufacturing, applying the method of claim 3 .
12. An airtight cap structure, manufactured by additive manufacturing, applying the method of claim 4 .
13. An airtight cap structure, manufactured by additive manufacturing, applying the method of claim 5 .
14. An airtight cap structure, manufactured by additive manufacturing, applying the method of claim 6 .
15. An airtight cap structure, manufactured by additive manufacturing, applying the method of claim 7 .
16. An airtight cap structure, manufactured by additive manufacturing, applying the method of claim 8 .